This invention relates in general to light sources, and more particularly, to programmable light sources.
The performance of passive low-light-level imaging systems that operate in the visible, near infrared, and short wavelength infrared spectral bands has been investigated for the past several years. Although such devices operate under low power, exhibit low dark current, and retain high system resolution under moonlight conditions, they are limited under low light level conditions.
Typically, their performance is evaluated in a laboratory setting using a 2856° K blackbody—a tungsten filament—as the radiation source, which can correlate reasonably well with night sky measurements below 1 micron. However, it does not correlate reasonably well with night sky measurements above 1 micron. Night sky spectral irradiance data indicate that a moonless sky produces over an order of magnitude more photons in the short-wave infrared (1 to 2 micron) waveband than in the visible and near infrared (0.4 to 1.0 micron) waveband. Therefore, the use of a single broadband 2856° K source in a laboratory to evaluate imaging systems that operate beyond 1 micron is insufficient.